Induction cooking appliances are more efficient, have greater temperature control precision and provide more uniform cooking than other conventional cooking appliances. In conventional cooktop systems, an electric or gas heat source is used to heat cookware in contact with the heat source. This type of cooking is inefficient because only the portion of the cookware in contact with the heat source is directly heated. The rest of the cookware is heated through conduction that causes non-uniform cooking throughout the cookware. Heating through conduction takes an extended period of time to reach a desired temperature.
In contrast, induction cooking systems use electromagnetism which turns cookware of the appropriate material into a heat source. A power supply provides a signal having a frequency to the induction coil. When the coil is activated a magnetic field is produced which induces a current on the bottom surface of the cookware. The induced current on the bottom surface then induces even smaller currents (Eddy currents) within the cookware thereby providing heat throughout the cookware.
Due to the efficiency of induction cooking appliances, precise control of a selected cooking temperature is needed. There are multiple means of controlling an induction cooking appliance. Some of these include mechanical switching, phase detection, optical sensing and harmonic distortion sensing. In some systems, these detection methods typically include a current transformer. However, current transducers yield an inconsistent and inaccurate output over a frequency range due to transformer loss principles. Moreover, current transformer packages can be expensive and have large package sizes and thus larger footprints.
Therefore, a need exists for a system and method of controlling an induction cooking appliance that overcomes the above mentioned disadvantages. A system and method that could control an induction cooking appliance based on a sample of a control signal would be useful. In addition, it would be advantageous to provide an induction cooktop system with the capability of sampling a control signal at a time interval triggered by the frequency of a power signal.